Having been on the other side of a Skype for Business installation I can tell you that it is extremely variable and can scale anywhere from a self-contained single server set-up[1] to a multi-region, multi-fail-over-cluster, highly available, extremely complicated set-up[2]. We had a few issues post initial install but spent the time to track them down to the point where our system was reliable and more usable than web ex and it's ilk. This is the crux of Lync, so much depends on your required set up and how well that was done.
Well, we're on MS Office 365 and all that it provides, including Skype. I have no idea how things could be so bad even with that (it used to be bad before with an on-premise installation too).
[1] - http://bressner.com/ucbox-express/ [2] - http://go.microsoft.com/fwlink/p/?LinkId=550989